This invention relates to fluorine-containing acrylic copolymers which impart durable oil- and water-repellency and dry soil resistance to substrates. This invention relates also to processes of treating fibrous and filamentary substrates so as to give them durable oil- and water-repellency and dry soil resistance. It relates also to aqueous emulsions containing such fluorine-containing polymers and to substrates treated with such emulsions, particularly nylon filaments and fibers.